Publication

EP 0831482 A3 19980415

Application

EP 97306368 A 19970820

Priority

• EP 97306368 A 19970820
• EP 96306934 A 19960924

Abstract (en)

[origin: EP0831482A2] According to the present invention there is provided apparatus for reading and writing data to a storage medium, wherein data is divided into fragments of predetermined length and each fragment comprises a marker, the apparatus comprising: means for detecting markers; means for extrapolating from the position of known markers to establish the position of an undetected marker. The present invention reduces the likelihood of data being unrecoverable as a result of unidentifiable marker patterns. Where a marker pattern is not detected, but a previous marker pattern within the data track has been successfully detected, the position of the missing marker is extrapolated from the position of the previous marker, using a knowledge of the relative spacing of markers which is predetermined by the data interchange format. In the embodiment to be described, each data fragment comprises a header containing ancillary information wherein the headers of the data fragments comprise the markers. Preferably, the extrapolation is done from the position of already-detected markers. to establish the position of subsequently undetected markers. Optionally, the extrapolation may be done in reverse from the position of subsequently-detected markers to establish the position of previously undetected markers. The apparatus may comprise means for setting a limit on the number of consecutively undetected markers whose position will be established by extrapolating from the position of a known marker. <IMAGE>

IPC 1-7

G11B 20/12; G11B 27/30

IPC 8 full level

G11B 20/12 (2006.01); G11B 27/30 (2006.01)

CPC (source: EP)

G11B 20/1209 (2013.01); G11B 27/3063 (2013.01)

Citation (search report)

• [XA] US 4700240 A 19871013 - UMEMOTO MASUO [JP], et al
• [XA] EP 0670555 A1 19950906 - OLYMPUS OPTICAL CO [JP]
• [A] US 4126887 A 19781121 - MIYAZAKI M [JP], et al
• [A] US 5353175 A 19941004 - CHIBA TAKAYOSHI [JP]
• [A] US 5446604 A 19950829 - CHIBA TAKAYOSHI [JP]
• [A] WO 8502284 A1 19850523 - STORAGE RES PTY LTD [AU]
• [A] US 4813011 A 19890314 - KULAKOWSKI JOHN E [US], et al
• [A] EP 0012897 A1 19800709 - TOKYO SHIBAURA ELECTRIC CO [JP]
• [A] MUIJTJENS A M M ET AL: "EXTRAPOLATION OF INCOMPLETE MARKER TRACKS BY LOWER RANK APPROXIMATION", INTERNATIONAL JOURNAL OF BIO-MEDICAL COMPUTING, vol. 33, no. 3/04, 1 November 1993 (1993-11-01), pages 219 - 239, XP000418427

Designated contracting state (EPC)

AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

DOCDB simple family (publication)

EP 0831482 A2 19980325; EP 0831482 A3 19980415

DOCDB simple family (application)

EP 97306368 A 19970820